1. Field of the Invention
The present invention relates generally to methods for providing connector assemblies on tube ends, and, more particularly, to a process for forming radially upset flanges to secure a connector on the end of a tube, and to a connector assembly formed by the process.
2. Description of the Related Art
It is known in fluid transportation systems utilizing tubes of steel, copper or other metals to form a connector assembly on the end of the tube, for connecting the tube to another component of the fluid system, or to a complementary connector assembly on another tube section. A connector assembly includes a tube and a connector provided on the tube at an end portion of the tube. The connector may take the form of a nut, a female connector of another design, or a male connector of suitable form and function. It is also known, when coupling together connector assemblies of adjacent fluid system components, to provide a sealing member associated with the connectors, to create a fluid tight seal. It may be required that the connector be permitted to rotate on the tube end, to establish the connection between the connectors, but the connection must be tight i.e., not permitting fluid to leak from the connector assembly. For a proper, fluid tight engagement between the connectors, any sealing member used must be properly positioned.
It is desirable to have the sealing member maintained in proper position by the structure of the connector assembly itself, to minimize the possibility that the sealing member would become mispositioned. It is also desirable that the connector assembly is axially secured near the end of the tube, that is the connector is restricted from moving significantly in either direction axially on the tube.
It also is known to provide a flared end on a tube, to provide a sealing surface against which the tube can be mated to another tube or system component. The flared end may also be used to prevent the connector from passing off the end of the tube. However, it is preferred that axial movement of the connector be inhibited by other than the flared end, as distortion of the flared end may result in fluid leakage at the connection. For this reason, radially outward upsets of the tube have been used to secure the position of the connector on the tube. Creating the radially outward upsets has been neither easy nor simple, often requiring multiple steps, increasing manufacturing expense.
What is needed is a simplified manufacturing process for securing a connector at the end of a tube. What is further needed is a tube and connector assembly which can be manufactured in a simple and efficient manner, and which incorporates the desirable features for such an assembly, including restraining the connector against axial movement on the tube and providing a sealing flange and a properly positioned sealing member for creating a fluid tight seal.
The present invention provides a process for forming radially outward upsets, or deformations, in tubes, in a simplified sequence of steps, and further provides a tube connector assembly formed by the process. Radially outward upsets can be formed substantially simultaneously at opposite ends of a connector positioned on the tube, and a sealing member can be secured in place on the tube while forming a flared end on the tube.
The invention comprises, in one form thereof, a method of securing a connector on an end of a tube. A connector is provided, having an end face and an away face. A desired length of tube is provided, having an end portion and a tube end. The connector is passed over the end portion of the tube, with the end face of the connector nearest the tube end and the away face of the connector farthest from the tube end. The tube is gripped with a fixture, and positioned with the away face of the connector against the fixture. A preferred length of the tube end portion extends axially beyond the end face of the connector. The end of the tube is impacted axially, causing a major radially outward upset of the tube against the end face of the connector and a minor radially outward upset of the tube against the away face of the connector. A tapered punch is forced into the tube axially, at the tube end, causing the end of the tube to flare outwardly. The tube is released from the fixture.
The invention comprises, in another form thereof, a tube end connector assembly. A length of tube has a tube end portion, a tube end and a tube axis. A connector is disposed on the tube end portion, the connector having an end face nearest the tube end and an away face. A major radially outward upset of the tube is disposed against the connector end face, and a minor radially outward upset of the tube is disposed against the connector away face.
The invention comprises, in yet another form thereof, a process for forming a flanged tube. A section of tube is provided, having a tube end. The tube is secured against axial movement by grasping the tube in a fixture. External support of the tube is provided along regions of the tube between the tube end and the fixture where a radially outward flange is not desired. Regions without external support are provided between the tube end and the fixture where a radially outward flange is desired. An axial force is applied to the tube end, causing portions of the tube to buckle outwardly at the regions without external support.
An advantage of the present invention is that a simplified manufacturing process is provided for securing a connector on a tube.
Another advantage of the present invention is in providing a tube end connector assembly which can be manufactured efficiently, having a connector secured near the end of the tube, with the connector restrained from axial movement along the tube.
Yet another advantage of the present invention is that a simplified manufacturing process is provided for forming flanged tubes with flanges in a plurality of discrete locations along the tube length.